Question

How do you prepare:

K₂MnO₄ from MnO₂?

Answer 1

K₂MnO₄ can be prepared from pyrolusite (MnO₂). The ore is fused with KOH in the presence of either atmospheric oxygen or an oxidising agent, such as KNO₃ or KClO₄, to give K₂MnO₄.

2 MnO₂ + 4 KOH + O₂ \[\to^\Delta\]2 K₂MnO₄ +2 H₂O

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